1. Field of the Invention
The present invention relates generally to devices for handling granular or flake material and, more particularly, relates to a fluid suspension enrobing apparatus for suspending granular or flake material during a treatment operation.
2. Discussion of the Prior Art
It is known, e.g. from U.S. Pat. No. 3,964,175, to Sivetz, to provide a processing apparatus for roasting coffee beans, wherein a box-like chamber is provided in which the beans are levitated as a dense, uniformly recirculating mass by an upwardly directed airstream of heated air.
According to the Sivetz patent, a batch type roaster includes a roasting chamber, a heated air plenum separated from the roasting chamber by a distributer plate and an inclined inner plate, and a blower. A front wall is provided on the roasting chamber at a position generally opposite the inner plate, and includes a door which permits access to the roasting chamber for loading and unloading the roasting chamber before and after a roasting operation is carried out. The door forms a part of the front wall of the batch type roasting device and remains shut during a roasting operation in order to prevent material from escaping the roasting chamber as the material is circulated up along the front wall during a roasting operation.
A continuous coffee roasting system is also disclosed in the noted Sivetz patent which permits coffee beans to be continuously fed to and delivered from a roasting device while roasting of the beans is carried out. According to the disclosure relating to this continuous system, a plurality of separate, vertically descending roasting chambers are provided which are connected together via inlet hoppers and delivery chutes such that as coffee beans are delivered from one chamber of the system, they enter the next.
Each chamber of the continuous system includes an air distributor plate separating the chamber from a plenum located beneath the chamber. A front wall rises vertically upward from the separator plate of each chamber and includes a sight glass through which the process may be viewed from outside the chamber.
It is also known to provide an enrobing device including an elongated chamber having a material inlet at one axial end thereof and an outlet at the opposite axial end. In these known enrobing devices, means are provided for dispensing a treatment fluid within the chamber such that material passing through the chamber is coated with the fluid as the material passes from the inlet to the outlet. Typically, the movement of the material through the chamber is carried out by rotating the inner wall of the enrobing chamber and by providing vanes on the inner wall that move the material as the wall rotates about the axis of the chamber.
Several features of the known material handling devices present drawbacks which prevent the devices from operating in the most beneficial manner when used in handling granular or flake materials that are to be submitted to a treatment operation. For example, because it is frequently required for an enrobing apparatus to include a dispensing mechanism for dispensing a coating material or the like into the treatment chamber, it would be advantageous to provide means for permitting quick access to the mechanism in order to enable cleaning and maintenance thereof without substantial disassembly of the apparatus being required.
Another drawback present in known devices resides in the lack of any provision in the device for permitting an operator thereof to take samples from the treatment chamber without turning the device off and allowing the material within the treatment chamber to settle to the bottom thereof. Thus, in the known devices, it is time consuming and difficult to check the material within the treatment chamber during operation to see if operational conditions within the treatment chamber are providing satisfactory results.
Such periodic testing of the material being treated in the treatment chamber of an enrobing device is important, especially in continuous systems, to insure that processing of the material is completed before the material is delivered from the treatment chamber.